Tampons are inserted by the wearer either by direct insertion via the fingers of the wearer or else by means of a tampon applicator. Tampons applicators have proven to be the insertion means of choice by a substantial proportion of tampon users in the United States. There are several considerations involved in the construction of applicators. These applicators are conventionally made either of a cardboard or a molded thermoplastic material. While applicators made of thermoplastic material are anesthetically desirable because they tend to cover the leading edge of the tampon pledget prior to insertion and resist absorption of bodily fluids, the relative cost of these applicators is substantially higher than the cost of comparable cardboard applicators. Since the applicators do not directly affect the products performance, but do have a direct affect on the overall cost of the tampon unit, it is desirable to provide inexpensive tampon applicators which means minimal use of material and simplicity of design particularly in the case of applicators made of thermoplastic material. Complex molding not only adds to the cost but produces undesirable flash which may injure the user.
Aesthetically, tampons are used in part for discreteness and portability and therefore the applicators should be as small as possible. The most often used tampon applicators are made in the form of telescoping tubes with inner tubes designed to be withdrawn from the rearward or gripping edge of the outer tube and then pushed back against the tampon pledget to expel the pledget through the insertion end or edge of the outer tube.
Because of the desirability for discreteness, several tampon tubes have been suggested which provide for positioning the tampon pledget within at least a portion of the inner tube. The leading edge of the inner tube is then compressed as the inner tube is withdrawn through the insertion end of the outer tube. The compression of the diameter of the leading end of the inner tube constricts the end to a diameter less than the pledget diameter and provides and edge for pushing the pledget out through the leading or insertion end of the outer tube. U.S. Pat. No, 4,276,881 describes such an applicator. U.S. Pat. No. 3,090,385 describes a tampon applicator with several extended fingers instead of an inner tube. These fingers are compressed by a ring fashioned as part of an inner surface of the outer tube.
U.S. Pat. No. 4,286,595 discloses another type of radially compressible inner tube with alternating slots and grooves. In each of the applicators described above, either the inner or outer tube requires some complicated structure either to provide a detent or a restraint for the reciprocal motion of the inner tube.